Conventionally, an acceleration/deceleration detector such as an acceleration sensor is known which detects acceleration/deceleration of a body to be measured (hereinafter, called “measurement object”). For example, Patent Literature 1 described below discloses a technology for detecting forward/backward accelerations by a forward/backward acceleration sensor while a vehicle travels in a predetermined vehicle speed region in which driving/braking force is substantially 0 a predetermined number of times, setting an average value of the forward/backward accelerations as a zero point offset value of the forward/backward acceleration sensor, and calibrating the detection value of the forward/backward acceleration sensor by the zero point offset value. Further, Patent Literature 2 described below discloses a technology for detecting a forward/backward acceleration by an acceleration sensor in a state that a vehicle stops as well as further detecting a forward/backward acceleration in a state that the vehicle is inverted its direction at the position where the vehicle stops and is stopped again and using an average value of the forward/backward accelerations as an offset error of the acceleration sensor.
Note that Patent Literature 3 described below discloses a technology for determining that an acceleration sensor is abnormal when an output value of the acceleration sensor exceeds only any one of an acceleration reference value or a deceleration reference value and a time during which the output value exceeds any one of them exceeds a reference time. Further, Patent Literature 4 described below discloses a technology of an apparatus which includes an acceleration detecting hole element disposed at a center, an annular rotor that rotates around the hole element, and a rotating position detecting means for detecting a rotating position of the rotor, calculates acceleration applied to the rotor based on a rotating position at which the rotor is kept until the rotor rotates 180° and on the rotating position detected by the rotating position detecting means, and cancels a drift amount which is an offset error of an acceleration sensor.